mod: Ext 13 — SLA sweep over pending lifecycle cases, 307/307

Composes lifecycle (Phase 3) with time (Ext 12): a timed-case pairs a case with
its state-entry tick; mod/overdue? flags pending cases (open/triaged/appealed)
past a deadline; mod/sla-sweep returns the breached report ids. Terminal states
never breach. Pure overlay — lifecycle stays timeless, caller stamps entry. +15 tests.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/mod/conformance.conf

@@ -21,6 +21,7 @@ PRELOADS=(
   lib/mod/whatif.sx
   lib/mod/batch.sx
   lib/mod/temporal.sx
+  lib/mod/sla.sx
   lib/mod/lifecycle.sx
   lib/mod/audit.sx
   lib/mod/api.sx
@@ -44,4 +45,5 @@ SUITES=(
   "whatif:lib/mod/tests/whatif.sx:(mod-whatif-tests-run!)"
   "batch:lib/mod/tests/batch.sx:(mod-batch-tests-run!)"
   "temporal:lib/mod/tests/temporal.sx:(mod-temporal-tests-run!)"
+  "sla:lib/mod/tests/sla.sx:(mod-sla-tests-run!)"
 )